Results 51 to 60 of about 3,875 (223)

Solar Vortex Detection with Velocity Field Normalization: Eliminating False Positives

The Astrophysical Journal
Small-scale vortices in the solar photosphere play a central role in transporting mass, energy, and momentum into the upper solar atmosphere, yet reliably detecting these structures remains rather challenging.
Lauren McClure, Suzana Silva, Gary Verth, Istvan Ballai, Viktor Fedun   +4 more
doaj   +1 more source

Spectral Irradiance Observations and Projections for Solar Cycle 25

Earth and Space Science, Volume 13, Issue 4, April 2026.
Abstract The Ozone Monitoring Instrument (OMI) on the Aura satellite makes near‐daily measurements of solar spectral irradiance (SSI) at wavelengths between 265 and 500 nm for instrument calibration purposes. The low degradation and exceptional stability of OMI's calibration during its lifetime facilitates the creation of a new 18‐year OMI Version 7 ...
Matthew T. DeLand, Sergey V. Marchenko, Judith L. Lean, Odele Coddington   +3 more
wiley   +1 more source

High-resolution Observations of a C9.3 White-light Flare and Its Impact on the Solar Photosphere

The Astrophysical Journal Letters
We present a detailed analysis of a C9.3 white-light flare using high-resolution observations from the New Vacuum Solar Telescope. The flare occurred near the eastern solar limb on 2023 September 11, within NOAA AR 13431, and produced beam electrons with
Zhe Xu, Xiaoli Yan, Zhentong Li, Liheng Yang, Zhike Xue, Jincheng Wang, Yian Zhou   +6 more
doaj   +1 more source

Reconstruction of Two‐Dimensional Magnetohydrodynamic and Hall Magnetohydrodynamic Equilibria in Space Using Physics‐Informed Neural Networks

Journal of Geophysical Research: Machine Learning and Computation, Volume 3, Issue 2, April 2026.
Abstract We present a novel data analysis technique based on physics‐informed neural networks (PINNs) to reconstruct two‐dimensional (2D) magnetohydrodynamic (MHD) and Hall MHD equilibria in a space plasma from in situ spacecraft measurements. Our method incorporates the steady‐state MHD or Hall MHD equations—a set of partial differential equations ...
Hiroshi Hasegawa, Eunjin Choi, Kyoung‐Joo Hwang, Kyunghwan Dokgo   +3 more
wiley   +1 more source

Coronal heating and wind acceleration by nonlinear Alfvén waves – global simulations with gravity, radiation, and conduction [PDF]

Nonlinear Processes in Geophysics, 2008
We review our recent results of global one-dimensional (1-D) MHD simulations for the acceleration of solar and stellar winds. We impose transverse photospheric motions corresponding to the granulations, which generate outgoing Alfvén waves.
T. K. Suzuki
doaj  

Photospheric Faculae and the Solar Oblateness [PDF]

The Astrophysical Journal, 1972
Photospheric faculae near the equatorial solar limb may provide the excess brightness which Ingersoll and Spiegel showed would explain Dicke and Goldenberg's oblateness measurement. Three lines of evidence support this statement: (1) the excess emission of faculae may arise in optically thin regions, as required by the Ingersoll-Spiegel hypothesis; (
Chapman, Gary A., Ingersoll, Andrew P.
openaire   +2 more sources

Reconstructing Historical Solar Indices for Predicting Past Space Weather Events

Space Weather, Volume 24, Issue 4, April 2026.
Abstract Modeling and forecasting the near‐Earth space environment, specifically the thermosphere, is particularly important because it affects the motion of low‐Earth orbit objects through atmospheric drag. Solar indices such as F10.7, S10.7, M10.7, and Y10.7 are commonly used as inputs to ionospheric and thermospheric density models.
Poshan Belbase, Denny M. Oliveira, Theodosios Chatzistergos, Gangkai Poh, Eftyhia Zesta   +4 more
wiley   +1 more source

Photospheric Swirls in a Quiet-Sun Region

The Astrophysical Journal
Swirl-shaped flow structures have been observed throughout the solar atmosphere, in both emission and absorption, at different altitudes and locations, and are believed to be associated with magnetic structures. However, the distribution patterns of such
Quan Xie, Jiajia Liu, Chris J. Nelson, Robert Erdélyi, Yuming Wang   +4 more
doaj   +1 more source

Evolutions of various solar indices around sunspot maximum and sunspot minimum years [PDF]

Annales Geophysicae, 2002
The smoothed monthly sunspot numbers showed that in many solar cycles, (a) during years around sunspot maxima, there was only one prominent maximum, but in some cycles there was a broad plateau. If the beginning and end of these are termed as first
R. P. Kane, R. P. Kane
doaj   +1 more source

Investigating Alfvénic wave propagation in coronal open-field regions

, 2015
The physical mechanisms behind accelerating solar and stellar winds are a long-standing astrophysical mystery, although recent breakthroughs have come from models invoking the turbulent dissipation of Alfvén waves.
Morton, Richard, Tomczyk, Steve, Pinto, Rui   +2 more
core   +1 more source